Back water trap for drains



Nov. 25, 1947.,

G. A. HULL ,431,399

BACK WATER TRAP FOR DRAINS 2 Shee'ts-Sheet 1 Filed May 28, 1945 INVENTOR.

[GEORGE A.HULL' ATTORNEYS Nov. 25, 1947. G. A; HULL 2,431,399

BACK WATER TRAP FOR DRAINS Filed May 28, 1945 2 Sheets-Sheet 2 I I v m l 1y FIGA.

INVENTOR.

GEORGE A. HULL ATTORNEYS Patented Nov. 25, 1947 UNITED STATES rinses PATENT @FFHCE 7 Claims.

The invention relates to back water traps and has for its object the obtaining of a construction which may be placed in a basement floor or other convenient accessible location and which in case of rise in water from the sewer will seal off connection to the drain. To this end the invention consists in the construction as hereinafter set forth.

In the drawings:

Fig. 1 is a vertical central longitudinal section through the trap;

Fig. 2 is a plane view thereof;

Fig. 3 is a cross section on line 3-3, Fig. 1, looking to the left or rear of the casing and showing the bucket in normal lowered position to open the valve;

Fig. 4 is a cross section on the line 44 of Fig. 1 showing the bucket in elevation position to close the valve.

A is a casing having at its upper end a recessed surrounding flange B for receiving a cover plate C. D is a nipple at the forward lower end of the casing for connection with the drain pipe D. E is a socket fitting at the rear lower end of the casing for connection with the sewer pipe E. The forward portion A of the casing is tapered and terminates in the portion A of the width substantially equal to the drain pipe D and in this narrow portion is located a gate valve member F. This is so fashioned that in its lowered position indicated in dotted lines, Fig. 1, it will seal the opening to the nipple D but in its raised position shown in full lines, will clear this opening. G is a bucket within the casing which is suspended from a lever H mounted on a cross shaft H which at its opposite ends rests in V-shaped brackets I on the side walls of the casing. The forward end portion of the lever H extends into a recess F in the valve member F and has an up-turned finger H which bears against the top wall of said recess. The arrangement is such that when the bucket G is filled with water and surrounded by air it will overbalance the valve member F raising the latter to the position shown in full lines, Fig. 1. On the other hand, the empty bucket will be overbalanced by the valve member F so that if water should rise within the casing to surround the bucket, the valve will be lowered in the position shown in dotted lines, Fig. 1. The valve F is guided in its downward movement by flanges J on the opposite sides of the casing portion A said guides including forwardly inclined portions J at their lower ends which cooperate with an inclined lower face F of the valve to force the latter to its seat. The bucket G has centrally there- 2 of an upwardly extending rod G which is pivotally connected at G to the lever I-I. Thus, during the angular movement of the lever, the bucket will remain always in upright position.

In use, the casing A is set beneath the floor with the upper face of its cover C flush with the floor. The nipple D is connected with the drain pipe B and the socket E with the sewer pipe E as before described and the bucket G is filled with water. Thus, the valve F remains normally in open position so as not to interfere with passage of the drain water from the pipe D' to the sewer E. If, at any time, the water backs up from the sewer, it will rise within the casing and by thus relieving the bucket of the weight of liquid contained therein, will permit the valve F to drop into engagement with its seat sealing 01f connection with the nipple D. The back water pressure will force the valve in tight engagement with its seal so as to prevent passage of water upward through the drain pipe. Whenever necessary, the cover plate C may be easily removed providing access to the elements which are within the casing. The cover plate C is secured by screws A engaging lugs A on the casing.

One of the advantages of the construction is that it is not dependent for its operation on the use of an air-filled float valve. It is a well known fact that such float valves will in time fill with water so as to be inoperative. Consequently, if

' the closing of the valve were dependent upon such a float valve, it might fail at the time when most needed. With my construction, however, should the bucket become inoperative through loss of its water content, the valve would automatically close which would call attention to that fact and would prevent any rise of water through the drain.

In order to insure the tight closing of the valve F against its seat F the lower end of the valve has a knife edge F which bears against this seat and scrapes off any obstructive matter adhering thereto. Pressure of the knife edge against the seat is effected by supporting the valve on the finger H at a point which is to the right of the center of gravity of the valve as viewed in Fig. 1. Thus, the lower end of the valve tends to swing toward the right and hold the knife edge against the seat while the valve is descending, In its final lowered position the inclined flange J will also press it against the seat to effect a waterproof seal. As a further precaution the front wall A and also the seat F are inclined which diminishes the likelihood of any sediment lodging thereon.

The cover plate B is preferably provided on its lower face with inclined drip flanges B with their lowest point over the bucket G. Thus, any condensation on the lower face of the cover will be directed into the bucket and will assist in keeping the same full of water.

What I claim as my invention is:

1. A back water trap comprising a casing having inlet and outlet connections, a vertically movable gate valve within said casing adapted in lowered position to close said inlet connection, and a counterbalance for raising said gate valve and holding the same normally in open position, said counterbalance including a bucket normally filled with water and surrounded by air being of itself insufficient in weight to hold said valve open whereby rise of water within said casing'will close said valve.

2. A back water trap comprising a casing having inlet and outlet connections, a gate valve adaptedin its lowered position to close said inlet connection, a lever for raising or lowering said gate valve, and a counterbalance suspended from said lever and including a bucket normally filled with water and surrounded by air; the weight of said bucket without its water content being insufficient to hold said valve in raised position whereby rise of water in said casing will close said valve.

3. A back water trap comprising a casing having inlet and outlet connections tothe lower portion thereof, said casing having a narrow portion adjacent said inlet connection, a gate valve located in said narrow portion and verticallymovable therein, a lever engaging the upper end portion of said gate valve to raise and lower the same, and a counterbalance suspended from said lever including a bucket normally filled with water within an atmosphere of air, said bucket being of itself insufiicient in weight to hold said valve in raised position whereby either the loss of its water content or the rise of water within said casing will lower said valve into its closed position.

4. A back water trap comprising a casing open at its topand provided with inlet and outlet connections to its lower portion, a cover for said casing adapted to be flush with the basement floor when said casing is located beneath said floor, a vertically movable gate valve within said casing adapted in its lowered position to close said inlet connection, a lever fulcrumed in said casing and connected to said valve to raise and lower the same, and a counterbalance including a bucket suspended from said lever normally filled with water and in an atmosphere of air; the weight of said bucket in itself being insufficient to hold said valve in its raised position whereby either loss of water content or the rise of water within said casing tosurround saidbucket will lower said valve to its closed position.

5. A back water trap comprising a casing hav- 4 ing inlet and outlet connections to its lower portion with a valve seat surrounding said inlet, a vertically movable gate valve within said casing adapted in lowered position to close said inlet connection, said valve having a knife edge at its lower end, a lever on which said valve is suspended so that the center of gravity of the valve is in rear of the point of suspension thereby pressing. the knife edge against the.valve seat, and a counterbalance for raising said gate valve and holding the same normally open, said counterbalance including a bucket normally filled with water and surrounded by air being of itself insufficient in weight to hold said valve open whereby rise of water within said casing will close said Valve and said knife edge will clear said seat to produce effectual sealing.

6. A back water trap comprising a casing having inlet and outlet connections to its lower portion, a vertically movable gate valve adapted in its lower position to close said inlet connection, a counterbalance for raising said gate valve and holding the same normally in open position, said counterbalance including a bucket normally filled with water being of itself insuflicient in weight to hold said valve open whereby rise of water within said casing will close said valve, a cover for the top of said casing, and drip flanges on the lower face of said cover extending over said bucket whereby any condensed water vapor on said cover will be directed into said bucket.

7. A back water trap comprising a casing having inlet and outlet connections, the wall of said casing through which said inlet passes being inclined and provided with a valve seat surrounding the inlet opening, a vertically movable gate valve within said casing having a knife edge at its lower end, a lever on which said valve is suspended, said lever engaging a recess in the valve and having an upwardly directed finger engaging the valve at a point at one side of the center of gravity thereof to press said knife edge against said seat, and a counterbalance for raising said gate valve and holding the same in normally open position, said counterbalance including a bucket normally filled with water being of itself insuflicient in weight to hold said valve open whereby rise of water within said casing will close said valve.

GEORGE A. HULL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

